So after a bit of looking the 7650 that is the default high score in donkey kong and radar scope may be a reference to namco. Perhaps they were saying thanks for galaxian.
"this is a form of Japanese wordplay called 'Goroawase' in which you use the phonetic pronunciations of a string of numbers (which can apparently have multiple pronunciations in Japanese) to make them sound kind of like other words. So breaking down our 7650 could yield:
7 = NA
6 = MU
5 = KO
0 = O
Or "NA-MU-KO-O", which sounds a whole lot like the company that put out the game: Namco."
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